1. Field of the Invention
The present invention relates to a pretensioner capable of increasing a tensile force of a webbing belt by pulling an anchor to which an end of the webbing belt is fastened or a buckle device in which a tongue provided at the webbing belt is attached constituting a seat belt device of a vehicle when rapid deceleration of the vehicle.
2. Related Art
A pretensioner (pre-loader) that is disclosed in Japanese Patent Application Laid-Open (JP-A) Nos. 2007-62600 and 2007-76493 includes a housing at which a cylinder and a gas generator are mounted. In the housing, a through hole that is through the inside and the outside is formed, and a wire where a base end thereof in a longitudinal direction is connected to a piston in the cylinder passes through and extends to an external portion of the housing.
Further, the housing is connected to a high-pressure gas jet passage where high-pressure gas from the gas generator passes through. When the high-pressure gas that has passed through the high-pressure gas jet passage is sent to the cylinder, the piston slides in the cylinder by the pressure of the high-pressure gas. As a result, the wire is pulled.
A leakage of the high-pressure gas from the through hole causes a loss of the pressure for sliding the piston. For this reason, in the pretensioner that is disclosed in JP-A No. 2007-62600 and 2007-76493, a cylindrical protective sealing member that is provided at the high-pressure gas jet passage is press-contacted to an opening end of the through hole at the side of the high-pressure gas jet passage, thereby preventing or suppressing a leakage of the high-pressure gas from the high-pressure gas jet passage to the through hole.
In the configuration disclosed in JP-A Nos. 2007-62600 and 2007-76493, the gas generator is mounted in the housing in an inclined state, such that the high-pressure gas jetted from the gas generator is directed toward the side of the sealing member of the protective sealing member (that is, the side opposite to the side of the cylinder or the piston at the high-pressure gas jet passage). However, even though the gas generator is mounted in the inclined manner, the high-pressure gas is blown over a wide range of the side of a protective member in the protective sealing member (that is, the side closer to the cylinder or the piston than the sealing member constituting the protective sealing member). For this reason, it is necessary that the wall thickness of the protective member constituting the protective sealing member is set to be large so as to be against the heat or pressure of the high-pressure gas. As a result, since the size of the protective sealing member is increased, even though the larger protective sealing member is used, the size of the housing is increased in order to secure a space of the high-pressure gas jet passage.